Post by morphout on Nov 30, 2010 1:45:09 GMT -5

Anyone know? I was always under the impression that EGR valves generally only opened under closed throttle decel, mine is opening partially at idle and seems like it's making it idle rough - the vacuum regulator (not the solenoid, but the round plastic thing) is allowing vacuum to pass to the EGR valve while the solenoid stays closed - this seems wrong to me. I discovered this after trying to chase down a new EGR code - p0400 - which doesnt seem to have any good solid tried'n'true solutions on here.

Post by buggzyy on Nov 30, 2010 20:02:32 GMT -5

Make sure the 2 hoses that connect to the throttle body are on the correct port. you should be able to pinch the yellow hose and the EGR should apply fully and stall the engine. Most common failure or problems are the vac. lines installed backward or the solanoid is faulty.

Post by buggzyy on Dec 2, 2010 1:17:05 GMT -5

Not likely they would swap positions on their own. stalling is at idle by pinching the yellow strip hose this is to test the they EGR system. the Vacuum regulator from what I have been told is to limit vacuum and control the apply so the diaphram doesn't flutter. And No your egr should not open at idle. I would check the solanoid it may be stuck or the valve it self is stuck open.

Post by morphout on Dec 4, 2010 18:53:16 GMT -5

Not likely they would swap positions on their own. stalling is at idle by pinching the yellow strip hose this is to test the they EGR system. the Vacuum regulator from what I have been told is to limit vacuum and control the apply so the diaphram doesn't flutter. And No your egr should not open at idle. I would check the solanoid it may be stuck or the valve it self is stuck open.

Ahh, good, I think the regulator may be the problem then. If I set up the system so that only the solenoid is in line with the valve, the valve doesn't open at idle. It is only when I connect the vacuum regulator that I have issues. I'll see if I can find a vacuum regulator to replace what I have, seems like it should be cheap enough.... Thanks!

Post by geraintcoslett on Aug 17, 2011 14:37:31 GMT -5

Bump

Trying to figure out my rough idle/ misfire I focused on the EGR system as a possible vacuum leak. As the OP mentioned my EGR valve is also opening even at idle.

Checked the EGR solenoid and the resistance is within spec but when applying a vacuum and hitting it with 12v the vacuum is not released. So I need a new solenoid. Because the EGR is still opening at idle I am also guessing that something is up with the vacuum regulator. Just wondering if the OP made the changes and fixed the issue?

Post by geraintcoslett on Aug 24, 2011 17:03:06 GMT -5

For those of you out there that are considering buying a new EGR solenoid (not the valve) it's worth taking it off your truck and pulling it apart first to see if it is clogged up. I removed mine becuase it was not allowing me to suck air through it. When you apply 12v to the connectors it is supposed to hold a vacuum and when it is not connected you should be able to suck air through from the black plastic end (not the silver metal end). When applying the voltage I could hear it clicking but nothing else was happening. Pretty easy to pull apart (look out for the spring, 2 red o-rings and the metal cap that is housed inside the black plastic end of the solenoid). Sure enough it was clogged up with carbon, I cleaned it out with a small diameter piece of wire. Put it back together, and tested with voltage and it now holds and releases a vacuum. Put it back on the truck and now my EGR valve is not open all the time. Both the valve and the solenoid are working as they should.

Wouldn't say my rough idle has disappeared but it is improving after I did this and added a new clean air filter. Still need to get into the throttle body and give it a good clean. Will post back once this has been done.